Nissan 300ZX spun rod bearing
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Originally Posted By: ChattZX
I agree, I'm thinking a 40 weight would alleviate that issue. Agreed? I guess Mobil 1 0W-40 would be a good choice then. What break in oil would you recommend?
No need for a special break-in oil.
I agree, I'm thinking a 40 weight would alleviate that issue. Agreed? I guess Mobil 1 0W-40 would be a good choice then. What break in oil would you recommend?
No need for a special break-in oil.
I can't help but wonder if this is a case where flow volume was reduced too much by having an overly thick oil. Bearing failures are more often due to starvation than due to viscosity breakdown IMO. I'm sure not saying run out and try 5w20, but 20w50 is pretty thick stuff for a non-track car. I'd probably have looked into something like M1 0w40, (or RP's own 0w40) or maybe one of the high VI Redline products in an Xw30 or Xw40 rating.
Thoroughly read VG30DETT's saga over in the Racing Oils section.
He was dealing with oil starvation under high cornering G's, but also got into a pattern of failures when he rebuilt the engine by only polishing the rod journals and putting in new bearings. If the engine is built with the wrong fits and clearances, no oil selection is going to make it live.
I recommend that you do not try to rebuild the engine by polishing up the old stuff, especially if the bearing failure has blued the crank and/or rods. I don't know what the supply situation is for older Nissan V6's, but buy a rotating assembly from a reputable remanufacturer that has a warranty. Then measure all of the fits and clearances before assembling the engine. Don't put it together until you know that everything is within Nissan's engine build specifications.
As for trying to improve on the stock engine, the Nissan V6 seems to require a larger-capacity oil pan, so a 6 or 7-quart unit would probably help a lot.
He was dealing with oil starvation under high cornering G's, but also got into a pattern of failures when he rebuilt the engine by only polishing the rod journals and putting in new bearings. If the engine is built with the wrong fits and clearances, no oil selection is going to make it live.
I recommend that you do not try to rebuild the engine by polishing up the old stuff, especially if the bearing failure has blued the crank and/or rods. I don't know what the supply situation is for older Nissan V6's, but buy a rotating assembly from a reputable remanufacturer that has a warranty. Then measure all of the fits and clearances before assembling the engine. Don't put it together until you know that everything is within Nissan's engine build specifications.
As for trying to improve on the stock engine, the Nissan V6 seems to require a larger-capacity oil pan, so a 6 or 7-quart unit would probably help a lot.
Originally Posted By: A_Harman
As for trying to improve on the stock engine, the Nissan V6 seems to require a larger-capacity oil pan, so a 6 or 7-quart unit would probably help a lot.
Agreed, and I'm surprised that this isn't the FIRST modification that Nissan enthusiasts perform given how small some Nissan sumps are, and how notoriously hard on oil some of the engines are. Added volume works wonders for oil temp, and cycling the oil through the engine less often reduces the mechanical shearing.
Of course I say that owning two old Chrysler big-blocks with stock oil pans and pickups, which are notorious for brief starvation on G-loading.... Plumber's plumbing and all that ;-)
As for trying to improve on the stock engine, the Nissan V6 seems to require a larger-capacity oil pan, so a 6 or 7-quart unit would probably help a lot.
Agreed, and I'm surprised that this isn't the FIRST modification that Nissan enthusiasts perform given how small some Nissan sumps are, and how notoriously hard on oil some of the engines are. Added volume works wonders for oil temp, and cycling the oil through the engine less often reduces the mechanical shearing.
Of course I say that owning two old Chrysler big-blocks with stock oil pans and pickups, which are notorious for brief starvation on G-loading.... Plumber's plumbing and all that ;-)
On the Corvette Forum, one of the engine builders said that he has seen more engine problems with people running Royal Purple than any other oil. He NEVERS recommends this oil for that reason.
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I'm leaning towards your overfilling the sump that led to your spun bearing. Does your owner's manual say it's OK to overfill? Let us know if a rod was bent.
I wouldn't be quick to blame RP either. If your sump temperatures were too high, I doubt there are tons of products out there that would handle high heat better than such a synthetic 20w-50.
Not to blame the oil, but I wouldn't be running that thick either, particularly with the oil pressures that you're seeing. RP makes decent oils in 5w-40 and 0w-40, too.
Not to blame the oil, but I wouldn't be running that thick either, particularly with the oil pressures that you're seeing. RP makes decent oils in 5w-40 and 0w-40, too.
Originally Posted By: INDYMAC
I'm leaning towards your overfilling the sump that led to your spun bearing. Does your owner's manual say it's OK to overfill? Let us know if a rod was bent.
If overfilling by 0.5 quarts caused it I'd hate to know what I did to my WRX overfilling it by almost 0.8 QUARTS! OH NO! IT MUST BE TRASHED OH NO.
Seriously.
I'm leaning towards your overfilling the sump that led to your spun bearing. Does your owner's manual say it's OK to overfill? Let us know if a rod was bent.
If overfilling by 0.5 quarts caused it I'd hate to know what I did to my WRX overfilling it by almost 0.8 QUARTS! OH NO! IT MUST BE TRASHED OH NO.
Seriously.
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I`d choose one of these oils. Both are cheap and can be bought at Walmart:
Mobil 1 15W50
Mobil 1 10W40HM
Both of these run insanely smooth in my car,with my nod going to the 15W50. According to Mobil and the voa`s here,they`re a couple of the strongest,if not the strongest otc oils.
Mobil 1 15W50
Mobil 1 10W40HM
Both of these run insanely smooth in my car,with my nod going to the 15W50. According to Mobil and the voa`s here,they`re a couple of the strongest,if not the strongest otc oils.
This engine is only 22 yo, and has only been driven 153K?
Why should it break?
As long as you didn't really zing it before the oil reached a reasonable temperature, I doubt that either the RP or the grade caused the failure.
These universal Nissan V-6s do seem to have their problems.
More likely a part failure than an oil induced one.
Why should it break?
As long as you didn't really zing it before the oil reached a reasonable temperature, I doubt that either the RP or the grade caused the failure.
These universal Nissan V-6s do seem to have their problems.
More likely a part failure than an oil induced one.
Originally Posted By: ChattZX
Originally Posted By: CATERHAM
Originally Posted By: ChattZX
Originally Posted By: CATERHAM
Back in the day it was 10W-30.
While the very heavy oil choice likely had little to do with the cause of the spun bearing it clearly is OTT heavy for street use.
I'd be interested to know what the rebuilders/tuners of the 300ZX give as a reason for such a heavy oil. I suspect it has to do with track use of the turbo version of the car and possibly oil starvation during high g cornering.
For street use I suggest starting with Red Line 0W-30 and fine tune yoour viscosity choice based on the minimum optimum oil pressure at elevated rev's. On the off chance that you could need something heavier you could blend in some RL 0W-40 or 5W-50.
I believe it is to cure some of the oil starvation issues on higher G corners. I'm unsure if I would run a 0W-30, as most people ironically spin bearings in these motors running a light weight oil. I'd probably want at least a 40 weight for summer months at least. I'd be open to any suggestions no matter the cost. This rebuild is going to cost a pretty penny as it is, so I won't skimp out.
If you don't want to "skimp out", install an oil pressure gauge which is an effective viscometer. This will tell you how much viscosity reserve you have every second you engine is running. It's also the only proper way to fine tune your viscosity choice to your applcation. It will of course also tell you if you're getting any oil starvation when cornering as unlikely as that may be on the street.
Having said that, in the meantime you could use some readily available M1 0W-40 (or RP 0W-40 for that matter). It will be heavier than necessary but being a high VI oil the disadvantages over the spec' 30wt will be minimized.
Z32's come stock with an oil pressure gauge. At full rpm with the RP 20W-50 it would be at about 80 psi.
Some OEM pressure and temperature gauges are not very accurate.
I want to see the result of the teardown, because I never see a dead or dying Nissan VG30 series engine with less than 220,000 miles.
Originally Posted By: CATERHAM
Originally Posted By: ChattZX
Originally Posted By: CATERHAM
Back in the day it was 10W-30.
While the very heavy oil choice likely had little to do with the cause of the spun bearing it clearly is OTT heavy for street use.
I'd be interested to know what the rebuilders/tuners of the 300ZX give as a reason for such a heavy oil. I suspect it has to do with track use of the turbo version of the car and possibly oil starvation during high g cornering.
For street use I suggest starting with Red Line 0W-30 and fine tune yoour viscosity choice based on the minimum optimum oil pressure at elevated rev's. On the off chance that you could need something heavier you could blend in some RL 0W-40 or 5W-50.
I believe it is to cure some of the oil starvation issues on higher G corners. I'm unsure if I would run a 0W-30, as most people ironically spin bearings in these motors running a light weight oil. I'd probably want at least a 40 weight for summer months at least. I'd be open to any suggestions no matter the cost. This rebuild is going to cost a pretty penny as it is, so I won't skimp out.
If you don't want to "skimp out", install an oil pressure gauge which is an effective viscometer. This will tell you how much viscosity reserve you have every second you engine is running. It's also the only proper way to fine tune your viscosity choice to your applcation. It will of course also tell you if you're getting any oil starvation when cornering as unlikely as that may be on the street.
Having said that, in the meantime you could use some readily available M1 0W-40 (or RP 0W-40 for that matter). It will be heavier than necessary but being a high VI oil the disadvantages over the spec' 30wt will be minimized.
Z32's come stock with an oil pressure gauge. At full rpm with the RP 20W-50 it would be at about 80 psi.
Some OEM pressure and temperature gauges are not very accurate.
I want to see the result of the teardown, because I never see a dead or dying Nissan VG30 series engine with less than 220,000 miles.
Take your time. Get measurements and pictures from the teardown. Ask your buddy to try to figure out why the engine kicked it (failure analysis) as he takes it apart. Take all the available data and his opinion and check with Nissan guys to see if they have any thoughts on the subject. Only then decide what needs to be different (if anything) to prevent this problem happening again. While the engine is still apart, decide if you want any other modifications before any machine work is done or any parts are purchased. Once the engine is back together and in the car is there anything you'll wish you'd done while it was being rebuilt? How about two years from now?
Originally Posted By: A_Harman
Thoroughly read VG30DETT's saga over in the Racing Oils section.
He was dealing with oil starvation under high cornering G's, but also got into a pattern of failures when he rebuilt the engine by only polishing the rod journals and putting in new bearings. If the engine is built with the wrong fits and clearances, no oil selection is going to make it live.
I recommend that you do not try to rebuild the engine by polishing up the old stuff, especially if the bearing failure has blued the crank and/or rods. I don't know what the supply situation is for older Nissan V6's, but buy a rotating assembly from a reputable remanufacturer that has a warranty. Then measure all of the fits and clearances before assembling the engine. Don't put it together until you know that everything is within Nissan's engine build specifications.
As for trying to improve on the stock engine, the Nissan V6 seems to require a larger-capacity oil pan, so a 6 or 7-quart unit would probably help a lot.
I gutting out the entire motor and rebuilding with forged rods, pistons and crank this time around.
Thoroughly read VG30DETT's saga over in the Racing Oils section.
He was dealing with oil starvation under high cornering G's, but also got into a pattern of failures when he rebuilt the engine by only polishing the rod journals and putting in new bearings. If the engine is built with the wrong fits and clearances, no oil selection is going to make it live.
I recommend that you do not try to rebuild the engine by polishing up the old stuff, especially if the bearing failure has blued the crank and/or rods. I don't know what the supply situation is for older Nissan V6's, but buy a rotating assembly from a reputable remanufacturer that has a warranty. Then measure all of the fits and clearances before assembling the engine. Don't put it together until you know that everything is within Nissan's engine build specifications.
As for trying to improve on the stock engine, the Nissan V6 seems to require a larger-capacity oil pan, so a 6 or 7-quart unit would probably help a lot.
I gutting out the entire motor and rebuilding with forged rods, pistons and crank this time around.
Originally Posted By: INDYMAC
I'm leaning towards your overfilling the sump that led to your spun bearing. Does your owner's manual say it's OK to overfill? Let us know if a rod was bent.
It was only overfilled by maybe half a quart or even less.
I'm leaning towards your overfilling the sump that led to your spun bearing. Does your owner's manual say it's OK to overfill? Let us know if a rod was bent.
It was only overfilled by maybe half a quart or even less.
The car before I bought it had a few neglected areas such as rusted out coolant and a really nasty radiator, so to be honest I don't know how well the engine was maintained before I bought it at 120,000 and it was owned by a woman all its life, so as we all know it probably had a few extended OCI's I would imagine. The 1990 300ZX motors had a few design flaws from the factory such as badly machined heads that they later corrected in future models, so I think as a whole this engine didn't have a great life before I bought it. I just hope to have it rebuilt so it can be tracked and daily driven reliably.
Agreed.
Sadly it is likely to be your fault.
Some lessons get learned the hard way.
Sadly it is likely to be your fault.
Some lessons get learned the hard way.
Originally Posted By: ChattZX
Those are some good ideas that I didn't consider. I will defiantly look into that. I'm also going to go with forged pistons this time, over the stock cast pistons. It should be nice with the already forged rods and crank.
??. Cast pistons (si-al eutectic) are absolutely preferred unless your boosting or running nitrous. BTW the NISSAN OEM CHINA filter is junk, too small and poorly engineered - dont run it. There is almost NO oil flow clearance around the fiberboard endcaps - esp for overly thick "track" oil. And China filter paper will always be suspect regardless of Nissan QA/QC. Run a low efficiency filter.
Those are some good ideas that I didn't consider. I will defiantly look into that. I'm also going to go with forged pistons this time, over the stock cast pistons. It should be nice with the already forged rods and crank.
??. Cast pistons (si-al eutectic) are absolutely preferred unless your boosting or running nitrous. BTW the NISSAN OEM CHINA filter is junk, too small and poorly engineered - dont run it. There is almost NO oil flow clearance around the fiberboard endcaps - esp for overly thick "track" oil. And China filter paper will always be suspect regardless of Nissan QA/QC. Run a low efficiency filter.
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